ABSTRACT
Studies of the role of actin in tumour progression have highlighted its key contribution in cell softening associated with cell invasion. Here, using a human breast cell line with conditional Src induction, we demonstrate that cells undergo a stiffening state prior to acquiring malignant features. This state is characterized by the transient accumulation of stress fibres and upregulation of Ena/VASP-like (EVL). EVL, in turn, organizes stress fibres leading to transient cell stiffening, ERK-dependent cell proliferation, as well as enhancement of Src activation and progression towards a fully transformed state. Accordingly, EVL accumulates predominantly in premalignant breast lesions and is required for Src-induced epithelial overgrowth in Drosophila. While cell softening allows for cancer cell invasion, our work reveals that stress fibre-mediated cell stiffening could drive tumour growth during premalignant stages. A careful consideration of the mechanical properties of tumour cells could therefore offer new avenues of exploration when designing cancer-targeting therapies.
Subject(s)
Actins/metabolism , Breast Neoplasms/pathology , Cell Proliferation , Cell Transformation, Neoplastic/pathology , Stress Fibers/pathology , Animals , Breast/pathology , Breast Neoplasms/genetics , Cell Adhesion Molecules/genetics , Cell Adhesion Molecules/metabolism , Cell Line , Cell Movement , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Datasets as Topic , Drosophila , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Male , Phosphorylation , RNA, Small Interfering/metabolism , Time-Lapse Imaging , Tissue Array Analysis , Up-Regulation , src-Family Kinases/metabolismABSTRACT
Plant specialized metabolism often presents a complex cell-specific compartmentation essential to accomplish the biosynthesis of valuable plant natural products. Hence, the disclosure and potential manipulation of such pathways may depend on the capacity to isolate and characterize specific cell types. Catharanthus roseus is the source of several medicinal terpenoid indole alkaloids, including the low-level anticancer vinblastine and vincristine, for which the late biosynthetic steps occur in specialized mesophyll cells called idioblasts. Here, the optical, fluorescence, and alkaloid-accumulating properties of C. roseus leaf idioblasts are characterized, and a methodology for the isolation of idioblast protoplasts by fluorescence-activated cell sorting is established, taking advantage of the distinctive autofluorescence of these cells. This achievement represents a crucial step for the development of differential omic strategies leading to the identification of candidate genes putatively involved in the biosynthesis, pathway regulation, and transmembrane transport leading to the anticancer alkaloids from C. roseus.
